Some inclination detectors use liquid in a vessel to determine deviation from true vertical by measuring the gravity vector. A light beam from a source is reflected on the surface of the liquid. The reflected light beam is incident on a detector. The location of incidence on the detector changes as the vessel is inclined.
Using a CCD line as a sensor, the location where the reflected beam strikes the detector can be provided as an output signal. Using two such detectors orthogonal to one another in a chevron pattern, the inclination in two orthogonal directions can be detected, as in U.S. Pat. No. 6,088,090.
WO 99/57513 shows a two-axis inclination detector having two light sources and two CCD lines, with a single, large, plano-convex ball lens. The diameter and height of this configuration are too large for many applications.
DE 196 10 941 A1 shows an inclination detector using an area sensor.
U.S. Pat. No. 4,159,422 shows a displacement sensor using a light-emitting diode and photocells which generate output signals proportional to radiation reflected from a pool of mercury.
Inclination detector improvements are needed which will provide for smaller overall size, low overall height, low cost, compatibility with modern sensor and data interface technologies, scalability for use in various applications with differing demands on working range, accuracy and size, and/or semi-automated manufacture.